1/2″ NPT Brass Dome Oil Sight Glass Manufacturer | High-Pressure level Plug

360° High-Transparency View】 Features a premium, crystal-clear borosilicate glass dome that provides an unobstructed, high-visibility 360-degree liquid monitoring viewport. Technicians can instantly inspect fluid color, clarity, and level changes from any angle.

Industrial Temperature & Pressure Rated】 Expertly engineered to withstand demanding industrial environments. This heavy-duty brass dome sight plug safely operates under pressures up to 145 PSI (10 bar) and temperatures ranging from -13°F to 392°F (-25°C to 200°C).

Rugged Brass & Borosilicate Construction】 Machined from heavy-duty solid brass paired with high-impact, thermal-shock resistant borosilicate glass. Sealed with a reliable NBR O-ring (or optional Viton) to ensure an absolute, drip-free hermetic connection.

Versatile OEM Applications】 Highly recommended as a reliable oil level indicator and sanitary sight window for industrial gearboxes, tanks, air compressors, hydraulic reservoirs, pumps, piping systems, and automotive machinery.

Flexible MOQ & Factory Support】 As a trusted global HVAC/R and fluid control components partner, Fanovo offers flexible MOQ options (supporting trial orders of tens to hundreds of pieces) and rapid lead times with 100% pre-delivery quality inspection.

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Technical Specifications & Product Information

Designed for performance and reliability in demanding industrial applications, the Fanovo Brass Dome Oil Sight Glass is a premium fluid monitoring solution. Below are the core technical details for this component.

Product Information Table

Item No. Size(mm) A(mm) B(mm) C(mm) D(mm) E(mm) F(mm) SW(mm) Temperature
FN-DHO1 1/4″ NPT 1/4″ 12 16 9 12 10 21 Temperature range can be customized
FN-DNO2 3/8″ NPT 3/8″ 13 16 11 16 13 24
FN-DHO3 1/2″ NPT 1/2″ 14 16 13 18 13 26
FN-DHO4 3/4″ NPT 3/4″ 17 16 20 25 15 36
FN-DHO5 1″ NPT 1″ 20 16 25 30 15 40
FN-DHO6 1/4″ G1/4″ 12 16 9 12 10 21
FN-DHO7 3/8″ G3/8″ 10 16 11 16 13 24
FN-DHO8 1/2″ G1/2″ 10 16 13 18 13 26
FN-DHO9 3/4″ G3/4″ 12 16 20 25 15 36
FN-DHO10 1″ G1″ 12 16 25 30 15 40
FN-DHO11 M12 M12x1 10 16 9 12 10 21
FN-DHO12 M12 M12x1.5 10 16 9 12 10 21
FN-DHO13 M14 M14x1.5 10 16 9 12 10 21
FN-DHO14 M16 M16x1.5 10 16 11 16 13 24
FN-DHO15 M20 M20x1.5 10 16 12 18 13 26
FN-DHO16 M22 M22x1.5 10 16 13 18 13 26
FN-DHO17 M26 M26x1.5 11 16 19 25 14 36
FN-DHO18 M27 M27x1.5 11 16 20 25 15 36
FN-DHO19 M33 M33x1.5 11 16 25 30 15 40

Core Advantages & Engineering Benefit

The specific combination of materials and design in the Fanovo Brass Sight Glass translates directly into superior performance and long-term value for critical equipment.

Unyielding Performance Under Pressure & Heat
The primary advantage lies in its robust construction. The solid brass body and fused glass window create a single, incredibly durable unit that maintains its structural integrity and leak-proof seal under conditions where plastics and other materials would fail. This makes it the definitive choice for pressurized systems like compressors and hydraulic power units, as well as high-temperature environments such as industrial gearboxes.

Guaranteed Clarity & Long-Term Readability
Unlike acrylic or polycarbonate, the natural glass window is virtually immune to chemical attack from aggressive fluids and will not cloud, yellow, or craze over time due to UV exposure or heat. Furthermore, its superior scratch resistance ensures the view of the fluid level, color, and cleanliness remains crystal-clear throughout the component’s entire service life, facilitating accurate and proactive maintenance.

Superior Durability & Corrosion Resistance
Brass is inherently resistant to corrosion and can withstand significant mechanical stress, vibration, and accidental impacts far better than plastic sight plugs. This ruggedness ensures a long service life, reduces the need for frequent replacements, and minimizes the risk of downtime caused by component failure in harsh industrial settings.

Your Direct Manufacturing Partner (OEM & Customization)
As the direct manufacturer, Fanovo offers more than just a standard part. We provide a partnership. We have the engineering and production capability to offer custom thread sizes, private labeling with your brand’s logo, and tailored designs for equipment manufacturers (OEMs) and large-volume distributors, ensuring you get a component that perfectly fits your application and supply chain needs.

Feature Specification
Product Name 1/2″ NPT Brass Dome Oil Sight Glass
Part Number FNV-7001 Series
Body Material Solid Hexagonal Brass (C36000 / CZ121)
Window Material Natural Glass, Fused
Thread Size 1/4″NPT、3/8″ NPT、1/2″NPT、3/4″ NPT、1″NPT、M12x1、M12x1.5、M14x1.5、M16x1.5、M20x1.5、M22x1.5、M26x1.5、M27x1.5、M33x1.5、G1/4″、G3/8″、G1/2″、G3/4″、 G1″
Maximum Pressure Up to 125 PSI (9 Bar)
Operating Temperature Up to 300°F (150°C)
Seal Integrity Achieved through a high-strength fusion process between glass and brass body
Chemical Resistance Excellent against mineral oils, petroleum, fuels, and most industrial fluids
Installation Standard hex body for easy installation with a wrench
Design Domed window for enhanced visibility

In addition to this size, we can also customize other sizes for you according to your needs.

If you have any other needs about this product, please feel free to contact us.

Complies with Lead Free Plumbing Laws, NSF/ ANSI 61, UPC/ CE, ISO 9001

For approval information, please refer to the products specification sheet. For any other information on product certification and documentation information, please contact Fanovo.

FANOVO STATEMENT OF WARRANTY & LIMITATION OF WARRANTY

Fanovo warrants, to our all purchasers, that its products which are delivered to its purchasers will be the kind described in the order or price list and will be free of defects in workmanship or material for a period of two year from the date of shipping to you, our purchaser.

Should any failure to conform to this warranty appear within two year after the date of the initial delivery to our purchaser, Fanovo will, upon written notification thereof and substantiation that the goods have been stored, installed, maintained and operated in accordance with Fanovo’s recommendation and standard industry practice, correct such defects by suitable repair or replacement at Fanovo’s own expense. If any valve alleged to be defective, is reported to Fanovo headquarter in China, it will be examined and, if found to be defective under the warranty, it will be replaced at no charge in future order.

THIS WARRANTY IS EXCLUSIVE AND IS IN LIEU OF ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR OTHER WARRANTY OF QUALITY, WHETHER EXPRESS OR IMPLIED, EXCEPT THE WARRANTY OF TITLE AND AGAINST PATENT INFRINGEMENT Correction of non-conformities, in the manner and for the period of time provided above, shall constitute fulfillment of all liabilities of Fanovo to our purchaser, with respect to the goods, whether based on contract, negligence, strict tort or otherwise, it is the intention of Fanovo that no warranty of any kind, whether express or implied, shall pass through our purchaser to any other person or corporation.

LIMITATION OF LIABILITY: FANOVO SHALL NOT UNDER ANY CIRCUMSTANCES BE LIABLE FOR SPECIAL OR CONSEQUENTIAL DAMAGES SUCH AS, BUT NOT LIMITED TO, DAMAGES OR LOSS OF OTHER PROPERTY OR EQUIPMENT, LOSS OF PROFITS, OR REVENUE, COST OF CAPITAL, COST OF PURCHASED OR REPLACEMENT GOODS, OR CLAIMS OF CUSTOMERS OF OUR INITIAL PURCHASER. THE REMEDIES OF OUR INITIAL PURCHASER, AND ALL OTHERS, SET FORTH HEREIN ARE EXCLUSIVE, AND THE LIABILITY OF FANOVO WITH RESPECT TO SAME SHALL NOT, EXCEPT AS EXPRESSLY PROVIDED HEREIN, EXCEED THE PRICE OF GOODS UPON WHICH SUCH LIABILITY IS BASED.

Fanovo is not just innovative products—we also provide wide-ranging capabilities, including design, manufacturing, and distribution. Each of these capabilities, as well as others, can be scaled to your needs – you can use as much or as little as makes sense for your product development.

Our Strengths

  • Design/Prototyping
  • Manufacturing & Assembly
  • Custom Labeling & Packaging
  • Inventory Management
  • Continuous Improvement & Refinement

If you’re looking for an established, financially secure partner who offers robust quality systems, validated processes, continuous improvement strategies, and a proven track record, you’ve come to the right place. Contact us and we will show you the major breakthroughs OEMs have experienced with us.

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